Selective killing p53wT lung cancer cells harboring Arg72 homozygote by a small molecular CypA inhibitor

TP53, encoding a well-known tumor suppressor p53, plays essential roles in tumor initiation and pro- gression, and is frequently mutated in lung cancer. However, pharmacological stabilization and reactivation of p53 have not been actively explored for targeted cancer therapies. Here, we identified a novel Cyclophilin A （CypA） small molecule inhibitor （ HL001 ） that induces non-small cell lung cancer （NSCLC） cell cycle arrest and apoptosis via restoring p53 expression, and further stabilizes p53 through inhibiting the MDM2-mediated p53 ubiqutination. The down-regulation of G3BP1 by HL001 also contributes to p53 stabilization by inhibiting p53 redistribution from nucleus to cytoplasm. Furthermore, HE001 selectively suppresses tumor growth in p53 wild-type NSCLC harboring Arg72 homozygous alleles （p53-72R） through disrupting interaction between MDM2 and p53-72R in a CypA-de- pendent manner. Finally, administration of HE001 alone or co-treatment with cisplatin promotes significant tumor suppression in orthotopic NSCLC mouse model. Collectively, our preclinical study demonstrated that HE001, a small molecule inhibitor of CypA, selectively activated p53WT 72R homozygote and thus inhibits growth of human lung cancer cells. The results presented here demonstrate that the utility of CypA inhibitors serve as an approach to the targeted therapy for individual lung cancer patient.